Changelog in v2: - fix a issue that the track memory of memslot is freed if we only move the memslot or change the flags of memslot - do not track the gfn which is not mapped in memslots - introduce the nolock APIs at the begin of the patchset - use 'unsigned short' as the track counter to reduce the memory and which should be enough for shadow page table and KVMGT This patchset introduces the feature which allows us to track page access in guest. Currently, only write access tracking is implemented in this version. Four APIs are introduces: - kvm_page_track_add_page(kvm, gfn, mode), single guest page @gfn is added into the track pool of the guest instance represented by @kvm, @mode specifies which kind of access on the @gfn is tracked - kvm_page_track_remove_page(kvm, gfn, mode), is the opposed operation of kvm_page_track_add_page() which removes @gfn from the tracking pool. gfn is no tracked after its last user is gone - kvm_page_track_register_notifier(kvm, n), register a notifier so that the event triggered by page tracking will be received, at that time, the callback of n->track_write() will be called - kvm_page_track_unregister_notifier(kvm, n), does the opposed operation of kvm_page_track_register_notifier(), which unlinks the notifier and stops receiving the tracked event The first user of page track is non-leaf shadow page tables as they are always write protected. It also gains performance improvement because page track speeds up page fault handler for the tracked pages. The performance result of kernel building is as followings: before after real 461.63 real 455.48 user 4529.55 user 4557.88 sys 1995.39 sys 1922.57 Furthermore, it is the infrastructure of other kind of shadow page table, such as GPU shadow page table introduced in KVMGT (1) and native nested IOMMU. This patch can be divided into two parts: - patch 1 ~ patch 7, implement page tracking - others patches apply page tracking to non-leaf shadow page table (1): http://lkml.iu.edu/hypermail/linux/kernel/1510.3/01562.html Xiao Guangrong (11): KVM: MMU: rename has_wrprotected_page to mmu_gfn_lpage_is_disallowed KVM: MMU: introduce kvm_mmu_gfn_{allow,disallow}_lpage KVM: MMU: introduce kvm_mmu_slot_gfn_write_protect KVM: page track: add the framework of guest page tracking KVM: page track: introduce kvm_page_track_{add,remove}_page KVM: MMU: let page fault handler be aware tracked page KVM: page track: add notifier support KVM: MMU: use page track for non-leaf shadow pages KVM: MMU: simplify mmu_need_write_protect KVM: MMU: clear write-flooding on the fast path of tracked page KVM: MMU: apply page track notifier Documentation/virtual/kvm/mmu.txt | 6 +- arch/x86/include/asm/kvm_host.h | 12 +- arch/x86/include/asm/kvm_page_track.h | 67 +++++++++ arch/x86/kvm/Makefile | 3 +- arch/x86/kvm/mmu.c | 199 ++++++++++++++++++-------- arch/x86/kvm/mmu.h | 5 + arch/x86/kvm/page_track.c | 257 ++++++++++++++++++++++++++++++++++ arch/x86/kvm/paging_tmpl.h | 5 + arch/x86/kvm/x86.c | 27 ++-- 9 files changed, 509 insertions(+), 72 deletions(-) create mode 100644 arch/x86/include/asm/kvm_page_track.h create mode 100644 arch/x86/kvm/page_track.c -- 1.8.3.1 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
